Question

我有一个名为searchdetails的表

id  sourcecity  destcity    viacity     distance    viewcount
1   Bangalore   Chennai     Hosur        348            215
2   Delhi       Patna       Moradabad   1087             13
3   Delhi   Manali  Chandigarh  553 81
4   Mumbai  Kolhapur        377 151
5   Delhi   Patna       1082    4
6   Chennai Munnar  Dindigul    586 29
7   Mumbai  Jaipur      1207    6
8   Chennai Salem       348 144
9   Chennai Salem   Vellore 369 7
10  Hyderabad   Goa Raichur 655 69
11  Delhi   Manali      538 200
12  Chennai Trichy      334 204
13  Delhi   Mehandipur  Mathura 302 7
14  Jaipur  Delhi       273 135
15  Chennai Trichy  Viluppuram  334 11
16  Bengaluru   Hyderabad       569 49
17  Chenani Trichy  Tindivanam  3137    1
18  Bhadrachalam    Rajahmundry     178 3
19  Hyderabad   Khammam     193 10
20  Bhadrachalam    Morbi       1608    1
21  Goa Morbi       1302    1
22  Meerut  Pathankot   Jalandhar   478 8
23  Bangalore   Hyderabad       569 160
24  Hyderabad   Morbi       1401    1

现在我想要基于最高viewcount的前5个唯一的destcity名称，其中sourcecity =“Chennai”。

答案应该是：

Trichy      204
Salem       144
Munnar  29

什么是SQL查询？

我试过了：

SELECT DISTINCT destcity, viewcount
FROM searchdetails
WHERE sourcecity = 'Chennai'
ORDER BY viewcount DESC
LIMIT 0, 5

但它不起作用。

Answer 1

这适用于SQL-Server

SELECT TOP 5 *
FROM (
    SELECT destcity, MAX(viewcount ) viewcount 
    FROM searchdetails 
    WHERE sourcecity ='Chennai'
    GROUP BY destcity
    ) X
ORDER BY viewcount DESC

thi是for mysql

SELECT *
FROM (
    SELECT destcity, MAX(viewcount ) viewcount 
    FROM searchdetails 
    WHERE sourcecity ='Chennai'
    GROUP BY destcity
    ) X
ORDER BY viewcount DESC
LIMIT 5

Answer 2

试试这个（如果是对于mssql）：

declare @table table (id int,sourcecity varchar(100),destcity  varchar(100),viacity  varchar(100),distance int,viewcount int)
insert into @table values (1,'Bangalore','Chennai','Hosur',348,215);
insert into @table values (2,'Delhi','Patna','Moradabad',1087,13);
insert into @table values (3,'Delhi','Manali','Chandigarh',553,81);
insert into @table values (4,'Mumbai','Kolhapur','',377,151);
insert into @table values (5,'Delhi','Patna','',1082,4);
insert into @table values (6,'Chennai','Munnar','Dindigul',586,29);
insert into @table values (7,'Mumbai','Jaipur','',1207,6);
insert into @table values (8,'Chennai','Salem','',348,144);
insert into @table values (9,'Chennai','Salem','Vellore',369,7);
insert into @table values (10,'Hyderabad','Goa','Raichur',655,69);
insert into @table values (11,'Delhi','Manali','',538,200);
insert into @table values (12,'Chennai','Trichy','',334,204);
insert into @table values (13,'Delhi','Mehandipur','Mathura',302,7);
insert into @table values (14,'Jaipur','Delhi','',273,135);
insert into @table values (15,'Chennai','Trichy','Viluppuram',334,11);
insert into @table values (16,'Bengaluru','Hyderabad','',569,49);
insert into @table values (17,'Chenani','Trichy','Tindivanam',3137,1);
insert into @table values (18,'Bhadrachalam','Rajahmundry','',178,3);
insert into @table values (19,'Hyderabad','Khammam','',193,10);
insert into @table values (20,'Bhadrachalam','Morbi','',1608,1);
insert into @table values (21,'Goa','Morbi','',1302,1);
insert into @table values (22,'Meerut','Pathankot','Jalandhar',478,8);
insert into @table values (23,'Bangalore','Hyderabad','',569,160);
insert into @table values (24,'Hyderabad','Morbi','',1401,1);

select top 5 destcity from @table where sourcecity='Chennai' order by viewcount desc

查询基于其他列desc数据选择不同的数据

2 个答案: